package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author wxy
 * @since 2022-06-01
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    // private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    //创建一个线程就可以
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //类初始化之后就要执行
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";

        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取消息队列中的订单信息  XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())//>
                    );
                    //2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //2.1.如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //3.解析消息中的订单信息,第一个参数是消息的id,添加数据的时候用了*
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        /*private class VoucherOrderHandler implements Runnable {

             @Override
             public void run() {
                 while (true) {
                     try {
                         //1.获取队列中的订单信息，take是个阻塞方法
                         VoucherOrder voucherOrder = orderTasks.take();
                         //2.创建订单
                         handleVoucherOrder(voucherOrder);
                     } catch (Exception e) {
                         log.error("处理订单异常", e);
                     }
                 }
             }
         }*/

        private void handleVoucherOrder(VoucherOrder voucherOrder) {
            //1.获取用户id，不能从UserHolder内取了，因为是个全新的线程
            Long userId = voucherOrder.getUserId();
            //2.创建锁对象，其实可以不用加锁，因为redis已经做了并发判断，这是为了防止redis失败的兜底
            RLock lock = redissonClient.getLock("lock:order:" + userId);
            //3.获取锁
            boolean isLock = lock.tryLock();
            //4.判断是否获取锁成功
            if (!isLock) {
                //获取锁失败,返回错误或重试
                log.error("不允许重复下单");
                return;
            }
            try {
                //代理对象也不能像之前一样获取，因为也是通过ThreadLocal
                proxy.createVoucherOrder(voucherOrder);
            } finally {
                //释放锁
                lock.unlock();
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    //1.获取pending-list中的订单信息  XREADGROUP GROUP g1 c1 COUNT 1  STREAMS stream.orders 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //2.1.如果获取失败，说明pending-list没有消息，结束循环
                        break;
                    }
                    //3.解析消息中的订单信息,第一个参数是消息的id,添加数据的时候用了*
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException interruptedException) {
                        interruptedException.printStackTrace();
                    }
                }
            }
        }
    }


    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            //2.1.不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            //2.1.不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2.为0，有购买资格，把下单信息保存到阻塞队列
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.3.订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.4.用户id
        voucherOrder.setUserId(userId);
        //2.5.代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.6.放入阻塞队列
        orderTasks.add(voucherOrder);
        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }*/



   /* @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            //尚未开始
            return Result.fail("秒杀尚未开始！");
        }
        //3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            //已经结束
            return Result.fail("秒杀已经结束！");
        }
        //4.判断库存是否充足
        if (voucher.getStock() < 1) {
            //库存不足
            return Result.fail("库存不足！");
        }
        Long userId = UserHolder.getUser().getId();
        //要在整个事务上加锁，这样获得锁的时候，里面的事务一定提交了
        //每次useId都是全新的对象，所以要先转为String，但是toString内部也是new了一个新的String对象，所以要用intern返回常量池的地址
        //synchronized (userId.toString().intern()) {
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        //boolean isLock = lock.tryLock(1200);
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock) {
            //获取锁失败,返回错误或重试
            return Result.fail("不允许重复下单");
        }
        try {
            //获取代理对象（事务）,因为spring是对代理对象的方法加了事务，这里不这样做，默认是调用this的createVoucherOrder方法，没有事务功能
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
        //}
    }*/

    //@Transaction注解是只能用在public方法上
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单
        Long userId = voucherOrder.getUserId();

        //5.1.查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //5.2判断是否存在
        if (count > 0) {
            //用户已经购买过了
            log.error("用户已经购买过一次");
            return;
        }
        //6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0)
                .update();
        if (!success) {
            //扣减失败
            log.error("库存不足！");
            return;
        }
        //7.创建订单
        /*VoucherOrder voucherOrder = new VoucherOrder();
        //7.1.订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //7.2.用户id
        voucherOrder.setUserId(userId);
        //7.3.代金券id
        voucherOrder.setVoucherId(voucherId);*/
        save(voucherOrder);
    }

}
